content: /*
   * Copyright (C) 2012 ZXing authors
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.alipay.hulu.ui.scan.camera.open;
  
  import android.hardware.Camera;
  import android.util.Log;
  
  /**
   * Abstraction over the {@link Camera} API that helps open them and return their metadata.
   */
  public final class OpenCameraInterface {
  
      private static final String TAG = OpenCameraInterface.class.getName();
  
      private OpenCameraInterface() {
      }
  
      /** For {@link #open(int)}, means no preference for which camera to open. */
      public static final int NO_REQUESTED_CAMERA = -1;
  
      /**
       * Opens the requested camera with {@link Camera#open(int)}, if one exists.
       *
       * @param cameraId camera ID of the camera to use. A negative value
       *  or {@link #NO_REQUESTED_CAMERA} means "no preference", in which case a rear-facing
       *  camera is returned if possible or else any camera
       * @return handle to {@link OpenCamera} that was opened
       */
      public static OpenCamera open(int cameraId) {
  
          int numCameras = Camera.getNumberOfCameras();
          if (numCameras == 0) {
              Log.w(TAG, "No cameras!");
              return null;
          }
  
          boolean explicitRequest = cameraId >= 0;
  
          Camera.CameraInfo selectedCameraInfo = null;
          int index;
          if (explicitRequest) {
              index = cameraId;
              selectedCameraInfo = new Camera.CameraInfo();
              Camera.getCameraInfo(index, selectedCameraInfo);
          } else {
              index = 0;
              while (index < numCameras) {
                  Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
                  Camera.getCameraInfo(index, cameraInfo);
                  CameraFacing reportedFacing = CameraFacing.values()[cameraInfo.facing];
                  if (reportedFacing == CameraFacing.BACK) {
                      selectedCameraInfo = cameraInfo;
                      break;
                  }
                  index++;
              }
          }
  
          Camera camera;
          if (index < numCameras) {
              Log.i(TAG, "Opening camera #" + index);
              camera = Camera.open(index);
          } else {
              if (explicitRequest) {
                  Log.w(TAG, "Requested camera does not exist: " + cameraId);
                  camera = null;
              } else {
                  Log.i(TAG, "No camera facing " + CameraFacing.BACK + "; returning camera #0");
                  camera = Camera.open(0);
                  selectedCameraInfo = new Camera.CameraInfo();
                  Camera.getCameraInfo(0, selectedCameraInfo);
              }
          }
  
          if (camera == null) {
              return null;
          }
          return new OpenCamera(index,
                  camera,
                  CameraFacing.values()[selectedCameraInfo.facing],
                  selectedCameraInfo.orientation);
      }
  
  }
  